The present invention relates to an improved polysiloxane-boron composition and more particularly to the addition of elastomeric polymers to polysiloxane-boron compositions having only recovering bounce elasticity to provide new compositions having both bounce elasticity and recovering stretch elasticity.
A group of polysiloxane-boron compounds displaying bounce elasticity have been widely known in commercial markets and products forms. This type of material is often referred to as bouncing putty. The viscosity of such material ranges from very high to very low. Medium viscosity forms of polysiloxane compounds displaying bounce elasticity are marketed as toys such as "Silly Putty" (TM) or "Wacky Putty" (TM). These materials can be easily molded or shaped into unique shapes or forms. Unlike the more common molding clays and molding doughs, these polysiloxane-boron materials do not dry out and become hard and brittle over time. Instead, they retain their plasticity, moldability or flexibility indefinitely.
The use of low to medium viscosity forms of polysiloxane-boron compounds is well known in the physical therapy field. In physical therapy applications these compounds are used in a dough-like form as a medium for muscle exercise. The material is pulled, stretched and kneaded to aid particularly in the rehabilitation of hand and arm muscles. The use of such materials for therapy applications is noted in U.S. Pat. No. 3,677,997. In U.S. Pat. No. 2,541,851 polysiloxane-boron compounds or bouncing putties are described as having the property of high bounce elasticity under suddenly applied compression stress and a high degree of plasticity when such stress is applied slowly. Further, in U.S. Pat. No. 3,350,344 the properties of organosilicone putty in general are described as being resilient and deformable.
The compositions of the prior art polysiloxane-boron compounds have not provided materials which have significant stretch elasticity or stretch recovery properties. These elasticity properties are indicated by the ability of a material to return to its original form after having been stretched, molded or shaped.
References in the literature show that the known polysiloxane-boron compounds behave as a liquid plastic material through the range of low to high viscosities. Thus, the liquid plastic state-of-the-art base putty materials must be physically reshaped after exposure to a slowly applied stretching stress before they can be similarly stretched again. In physical therapy applications, this property of inelastic stretch (inelastic stretch recovery) in the known polysiloxane-boron compounds results in ineffective therapy. It follows that ineffective therapy generally requires the prescription of additional therapy regimes at additional expense and cost of time to the patient.
The compositions of the prior art polysiloxane-boron materials have not provided a class of materials displaying stretch elasticity or stretch recovery properties after elastic stretching thereof. It is therefore a principal object of the present invention to overcome such deficiencies of known polysiloxane-boron compounds and provide a bouncing putty type material which displays both bounce elasticity (compression stress recovery) and stretch elasticity (stretch stress recovery).